Video surveillance has been a much used security tool for years, and as a result of new breakthroughs in technology, security cameras are more effective than ever. Critical infrastructure, banks, retail stores, and countless other end-users depend on the protection provided by video surveillance. In the art of video surveillance, camera placement is becoming more complex and costly. Traditionally, two dimensional floor plan or site map-based automatic camera placement approaches has addressed the problem to some extent. This simplifies the problem by estimating the camera coverage area on a two dimensional plane. However, this provides only an approximate solution because these approaches ignore the elevation or height of structures in the area to be monitored. For example, it is difficult for this approach to distinguish an occlusion by a half wall (such as cubicle or desk) or a whole wall. Therefore, it is helpful to visualize and evaluate the approximate solution so as to give a precise solution to meet the video surveillance requirement, especially for critical infrastructures, before the installation of the surveillance system.
While two dimensional floor plans have been widely used, three dimensional geometry models of buildings are now available (for example, the BIM model). With the three dimensional model, it is possible to adopt the geometry technology to calculate the coverage area on the surface object, such as a floor, a wall, or a column, according to the frustum of the camera. Normally, a three dimensional method will export three dimensional polygons as the coverage area and then highlight these polygons to visualize the coverage area. The method can consider the occlusion effect and the altitude of the camera in the 3D environment. However the computing of the occlusion region is very intensive. Additionally, it is difficult to provide interactive operation for camera placement, such as real time adjustment of a camera's extrinsic parameters (position, orientation) and intrinsic parameters (field of view, focus length).